Sharpening device for the rotating sickle knife of cigarette rod machines



Sept. 29, 1942. P, U E 2,297,468

- SHARPENING DEVICE FOR THE ROTATING SICKLE KNIFE OF CIGARETTE RODMACHINES Filed May 28, 1940 2 Sheets-Sheet 1 I71 yen for Pa u 2 LouisGr'zu an cr Sept. 2%, 1942. A P. L. GRAUPNER SHARPENING DEVICE FOR THEROTATING SICKLE KNIFE OF CIGARETTE ROD MACHINES 2 Sheets-Sheet 2 FiledMay 28, 1940 Inventor-z PauZ Loud: GPaUpnCr W Patented Sept. 29, 1942SHARPENING DEVICE FOR THE vROTATING SICKLE KNIFE OF CIGARETTE ROD MA-CHINES Paul Louis Graupner, Dresden-Radebeul, Germany; vested in theAlien Property Custodian Application May 28, 1940, Serial No. 337,710 InGermany June 3, 1939 4 Claims. (01. 51-247) t This invention relates toa sharpening device for the rotating sickle-shaped knife of cigaretterod machines.

Sharpening devices for the mentioned purpose are known provided with acarrier for the-grinding disc rotating in the same direction as thesickle knife itself, the rotating axis of said carrier being parallel orapproximately parallel to the rotating axis of the knife and thegrinding disc engaging the cutting edge of the rotating sickle knifeduring the execution of each rotation. These grinding devices have beensatisfactory, however there is still the disadvantage that the so-calledface, i. e., the bevelled cutting edge of the generally relatively broadknife does not engage the eounterface of the grinding disc withoutvarying pressure. If the sickle knife which, as known, consists of athin metal sheet is pressed relatively hard against the grinding disc sothat all portions of its face over the whole length of the cutting edgeengage the grinding disc, it then necessarily follows that the cuttingedge is weakened irregularly by the grinding tool, i. e., one portion ofthe cutting edge is weakened in a higher degree than another portion sothat finally the cutting edge loses its sickle shape and is no longercapable of constantly executing an exact cut. As however the cigaretterod machine operates at an extremely high velocity an exact cut is ofthe highest importance.

The invention deals with the problem to attain an equal and regularengaging of the cutting edge with the grinding too] even if the knife isextremely broad and engages a corresponding broad face of the grindingtool, and to control the engagement in such a way that the same pressureexists and the wear on the face is equal on all parts of the cuttingedge. Further the sickle shape of the knife is maintained.

When solving this problem it is to be considered that the knife ismounted on a carrier rotating about an axis and is arranged obliquely onits carrier in such a manner that the points of the cutting edgefollowing one another during the cut move with the guiding tube of thecigarette rod and execute a screw-like movement to follow the motion ofthe rod and also of the guiding tube.

In consideration of this circumstance the invention consists thereinthat a grinding disc having a fiat side face to engage the cutting edgeof the sickle knife, is carried by the shaft of a planet-wheel rotatingaround a stationary sunwheel, the rotating axis of said grinding discbeing obliquely adjusted with respect to the axis of the sun-wheel thesaid axis of the sun wheel being itself obliquely adjusted with respectto the rotating axis of the knife carrier.

In this way the advantage is attained in that the grinding tool executessuch a rotating movement and during each rotation the grinding toolengages one time. the cutting edge of the also rotating sickle knife.However due to the mentioned movement of the said both means, thecutting face of thesickle knife is evenly stropped during its passagealong the face of the grinding disc without any stronger pressurearising at one portion of the cutting edge than at another.

To attain the greatest possible adjustability it is sufficient torotatably mount the axis of the sun-wheel around the driving shaft of abevel gear driving the shaft of the planet-wheel and to arrange. theaxis of the sun-wheel obliquely to said driving shaft.

The annexed drawings show one embodiment of the invention by way ofexample, but many alterations may be made without departing fromthespirit of the invention.

Fig. 1 of the drawings is a plan view of a part of a cigarette rodmachine showing the drive of the knife and the. grinding device and Fig.2Jis a side view thereof.

The shaft l of the sickle knife 32 is journalled in two bearings! and 3fixed to or integral with a block or frame 40 forming a portion of themachine frame. This shaft is obliquely arranged with respect to theguiding tube 4 of the cigarette rod 4!, said guiding tube being fixed torods 42 which are slidably guided in the machine frame and arereciprocated in a known manner by means of a crank-like device by themain shaft 43 journalled in the block 40.

The block 40 isprovided with a box or bearing 5 carrying a shaft 6. andhaving a reduced portion 1 around which a shell 8 is provided. Thisshell may be fixed in any desired position on the reduced portion 1 bymeans of a screw 9. The shell 8 is provided with a curved projection 10carrying a bearing l3 in which a shaft I 4 is rotatably mounted. To theone end of the shaft M the bifurcated end l5 of an arm 44 may be clampedin any desired position by means of a screw IS, the opposite end ofwhich arm being provided with a bearing 20 in which a shaft 2| isjournalled. Th shaft 2| carries a fiat grinding disc 23 revolving in thedirection of the arrow 22.

The drive of the knife and the grinding disc is derived from the mainshaft 43 to which the bevel 4 the sun-wheel 30 is arranged, but thissun-M wheel is not fixed to the shaft l4, but to the bearing l3 and isstationary. It is shaped as a spurwheel and meshes with a gear 3| beingthe planet-wheel fixed to the shaft 2| and provided with oblique teeth.

The axis of the shaft 2| is obliquely arranged with respect to the axisM of the sun-wheel, as shown in Fig. 2 of the drawings. The obliquity ofsaid axis must be so chosen that the resulting movement of the grindingdisc 23 corresponds to the movement of the knife in the desired manner,i. e., so that the grinding pressure is constant over the whole lengthof the cutting edge. The correct obliquity can be easily determined bytests.

When the bevel gear 29 rotates the shaft l4 and the arm 44 with thebearing 26 also rotate. Hereby the planet-wheel 3| runs around thestationary sun-wheel 36 and, rotates with its shaft 2|, the grindingdisc 23. The grinding disc in consequence thereof executes a planetarymovement around the sun-wheel and at the same time rotates around itsaxis.

The path of the grinding disc 23 may be adapted to the movement of thesickle knife 32 in consequence of the adjustability provided for.

The movement of the sickle knife 32 with respect to the guiding tube 4is produced by arranging the axis of the sickle knife obliquely to theaxis of the guiding tube 4. Further the carrier 31 of the knife 32 maybe obliquely adjusted in a known manner on the block 35 by means of theset screws 34, the block 35 being fastened to the shaft I.

It is to be understood that the face 36 of the knife must be maintainedin its regular and correct form when engaging the grinding disc 23. Forthis purpose the fiat grinding disc 23 must engage the sickle knifealways with the same pressure.

When rotating around the axis all points of the cutting edge 36 lie on aface of rotation with respect to the axis Therefore, in consequence ofthe arrangement and adjustability of the parts, the rotation of thegrinding disc 23 may be controlled in such a manner that said grindingdisc always engages the cutting edge 36 of the sickle knife 32 with thesame pressure during the time in which it contacts with the knife 32.

Therefore the cutting edge is equally groun The knife 32 may be adjustedradially to the axis within its carrier 31, if it is worn out so thatthe cutting dge 36 may always be retained in its proper position.

I claim:

1. A sharpening device for the revolving sickle knife of cigarette rodmachines, comprising, in combination, a revolving carrier, a sickleknife obliquely mounted on said carrier, a second carrier revolving inthe same direction of rotation .as the first mentioned carrier, asharpening tool rotatably mounted on said second carrier and having aflat grinding face adapted to engage the cutting edge of said sickleknife during each revolution of said knife, a shaft rotatably arrangedon said second carrier by which said sharpening tool is driven, a planetwheel for said tool, and a stationary sun wheel arranged coaxially withthe rotating axis of the said second carrier and engaging said planetwheel, the said shaft being obliquely arranged with respect to the axisof the sun wheel.

2. A sharpening device as claimed in claim 1 in combination with asecond shaft mounted at right angles to the rotating axis of the firstmentioned carrier, means for driving said second shaft, a third shaftcarrying said second carrier, being arranged obliquely with respect tothe said second shaft and coaxially with said sun wheel and a bevelgearing connection between said second and third shaft.

3. A sharpening device for the revolving sickle knife of cigarette rodmachines, comprising, in combination, a revolving carrier, a sickleknife obliquely mounted on said carrier, a second carrier revolving inthe same direction of rotation as the first mentioned carrier, asharpening tool rotatably mounted on said second carrier and having afiat grinding face adapted to engage the cutting edge of said sickleknife during each revolution of the knife, a shaft rotatably arranged onsaid second carrier by Which said sharpening tool is driven, a planetWheel for the tool, a further shaft on which said second carrier isadjustably mounted, and a stationary sun wheel arranged coaxially withsaid further shaft and meshing with said planet wheel, the firstmentioned shaft being obliquely arranged with respect to the axis of thesun'wheel.

4. A sharpening device as claimed in claim 1 in combination with asecond shaft mounted at right angles to the rotating axis of the firstmentioned carrier, means for driving said second shaft, a third shaftcarrying said second carrier, being arranged obliquely with respect tothe said second shaft and coaxially with said sun wheel, a bearing forsaid third shaft arranged adjustably with respect to the axis of thesaid second shaft and a bevel gearing connection between said second andthird shaft.

PAUL LOUIS GRAUPNER.

